Loftus & Palmer

To see the effect of leading questions on memory of an event (i.e. if changing verb in question about speed will affect speed estimates of participants)

Laboratory Experiment:

Participants shown seven clips of car accidents; asked to give account of clips; asked too answer specific question, including leading question

Independant Variables (Conditions):

smashed; collided; bumped; hit; contacted

Dependant variable:

Estimate of speed given by participants

'Smashed' - 40.8 mph

'Collided' - 39.3 mph

'Bumped' - 38.1 mph

'Hit' - 34. 0 mph

'Contacted' - 31.8 mph

• Participants' answers were affected by demand characteristics
• Wording of question causes an actual distortion in the participant's memory of accident

Participants watch 1-minute clip containing 4-second scene of car accident; asked to give account and then questioned; leading question

 Independant Variables (Conditions): 

'Smashed'; 'Hit'; Control group (no speed question asked)

Dependant Variable:

Answer to whether or not broken glass was seen: Yes; No

Week later participants asked further questions; critical question was: "Did you see any broken glass?"

             'Yes' broken glass     'No' broken glass

Smashed                   16                                              34

Hit                                7                                              43

Control                         6                                              44 

Two types of info which make up memory of complex event:

• Info gained from perceiving event
• Info we received after event

Questions actually alter people's memories

• Students
• 45 students (5 groups of 9) in Experiment 1
• 150 students (3 groups of 50) in Experiment 2